Colloidal aggregates exposed to shear flow exhibit a size-dependent qualitative behavior [Becker et al JCIS, 339, 362-372, 2009]. Under the same flow conditions small aggregates rotate like rigid bodies, whereas larger aggregates change their structure and even bigger aggregates break In this study the transition from the rotational regime to the restructuring regime is investigated by DEM simulations We applied a model for tangential interaction, capable of supporting bond-bending moments and torsional torques [Becker, Briesen, Phys Rev E, 78, 2008, 061404]. The probability for an aggregate to be affected by restructuring changes with the number of primary particle from zero to one in a small interval The probability becomes a master curve being independent of the shear flow and the interparticle interactions if it is represented as a function of the relative deviation from the critical particles number, i e. the number of primary particle where the probability of restructuring is equal to 05 Investigating the dependency of the critical particle number on the shear rates reveals power law relations which adequately represents the data. The exponents in the power law relations can particularly obtained from a fractal scaling argument (C) 2010 Elsevier Inc All rights reserved